In its fourth year, #SpiritDay captures major support | VIDEOS

All sorts of days are set aside to observe and raise attention to a number of causes and issues, but few have received such attention in such a short period of time as Spirit Day, which is celebrating its fourth year today.

People across the country are encouraged to wear purple clothing and change their Social Media profile images to purple today to speak out against bullying and to show support LGBT youth.

The simple idea with a big impact came from a Facebook post in 2010 by teenager Brittany McMillan, who wanted to remember the young people who had lost their lives to suicide, while taking a stand against bullying. McMillan's post went viral and people across the country participated in her grassroots campaign.

"Ultimately, I want Spirit Day to make just one person feel a little bit better about his or herself, to feel safe enough in their own skin to be proud of who they are," McMillan said.

Since that first year, national LGBT media advocacy organization GLAAD has partnered with McMillan to promote Spirit Day.

In the video below, McMillan speaks more about Spirit Day and why she started it.

How to get involved today

Participating in Spirit Day is easy. Readers who see this story before leaving for the day can put on a purple article of clothing to wear for the day.

Spirit Day is a very Social Media heavy campaign and people can also participate by "purpleizing" their profile images. GLAAD provides an easy tool that will automatically add a purple tint to people's Facebook and Twitter profile images HERE.

GLAAD also provides a Spirit Day resource kit which shares other ideas on how to participate today.

When posting on Social Media about the day, participants should use hashtag #SpiritDay.

Spirit Day gets major support

What started as a simple Facebook post by a teenager in Canada, has become a movement that has been noticed by numerous celebrities, politicians, and other high profile people and organizations.

The list of notable people participating this year is long, but is a testament to the importance of this work.

Erick McCormack and Debra Messing, stars of "Will & Grace," reunited this morning for the show's 15th anniversary on "TODAY" and were both sporting purple Spirit Day ribbons.

Logo TV has purplelized its logo and viewers will see the purple logo and scrolling messages letting people know about Spirit Day all day long.

CBS, CBS Radio and Showtime networks have also gone purple for the day.

Oprah Winfrey and her OWN Network are also supporting Spirit Day this year. Winfrey has "purpleized" her Twitter profile image, encouraging her 21.5 million followers to stand up against bullying.

Oprah.com is also sharing a video from Shane Bitney Crone, whose documentary "Bridegroom" will premiere on OWN on Oct. 27. The documentary is about why Spirit Day matters to him and so many others around the country.

Check out the GLAAD Blog for more stories about other supporters of Spirit Day 2013.